n3 Counsel for plaintiffs direct our attention to numerous cases that they contend establish that parol evidence may never be used to show a collateral agreement contrary to a term that the law presumes in the absence of an agreement. In each of these cases, however, the decision turned upon the court's belief that the writing was a complete integration and was no more than an application of the rule that parol evidence cannot be used to vary the terms of a completely integrated agreement. (Cf. discussion in Mangini v. Wolfschmidt, Ltd., supra, 165 Cal.App.2d 192, 203.) In Gardiner v. McDonogh, supra, 147 Cal. 313, 319, defendants sought to prove a collateral agreement that beans sold them were to conform to a sample earlier given. The court purportedly looked only to the face of the writing to decide whether parol evidence was admissible, and such evidence would be excluded if the writing was "clear and complete." Defendants argued that the written order was not complete because it did not fix a time and place of delivery, but the court answered that the failure to state those terms did not result in incompleteness because the law would supply them by implication. This decision was based on the belief that the question of admissibility had to be decided from the face of the instrument alone. Virtually every writing leaves some terms to be implied and almost none would qualify as integrations without implying some terms. The decision was therefore a product of an outmoded approach to the parol evidence rule, not of any compulsion to give conclusive effect to presumptions of implied terms.

     [Balance of footnote with other examples to the same effect is omitted.]